Shortwave and microwave diathermy

Question 1

What is diathermy?

Answer 1

application of high frequency electrical energy that is used to generate heat in the body tissues as a result of the resistance of the tissue to the passage of energy

Question 2

Do diathermies create muscle or nerve depolarization?

Answer 2

no, their wavelengths are too short

Question 3

What are the responses to diathermy?

Answer 3

increased blood flow, metabolic rate
dilation of blood vessels
muscle relaxation
heightened pain threshold
enzymatic activity is stimulated
decrease tissue/joint stiffness

Question 4

How much temperature can reduce mild inflammation and increase metabolism?

Answer 4

1 degree C

Question 5

How much temperature can decrease pain and muscle spasm?

Answer 5

2-3 degrees C

Question 6

How much temperature can cause tissue extensibility?

Answer 6

3-4 degrees C

Question 7

What will greater heating effect?

Answer 7

greater collagen elongation

Question 8

Heating occurs in proportion to what?

Answer 8

in proportion to the square of the current density and in direct proportion to the resistance of the tissue

Question 9

Heating=?

Answer 9

current density^2 x resistance

Question 10

How is non thermal diathermy useful?

Answer 10

Sodium tends to accumulate in cells due to the inhibition of the sodium/potassium pump during the inflammatory process creating a negative environment. Diathermy can create a magnetic field that can reactivate the pump to regain normal balance.

Question 11

What are the advantages of diathermy?

Answer 11

provides heating area larger than ultrasound
hands free treatment that doesn’t need constant monitoring
provides deeper heat than moist hot packs

Question 12

What is specific absorption rate (SAR)?

Answer 12

determines the amount of energy absorbed per unit of area of tissue mass

Question 13

What does a shortwave generator have?

Answer 13

radio frequency oscillator, amplifier, output resonance tank, electrodes, power supply, monitors, and controls

Question 14

What is dose I?

Answer 14

no sensation of heat

Question 15

What is doe II?

Answer 15

mild heating sensation

Question 16

what is dose III?

Answer 16

moderate heating sensation, comfortable heating

Question 17

What is dose IV?

Answer 17

vigorous heating that is tolerable below the pain threshold

Question 18

What kind of field does a shortwave with 13.56 MHz produce?

Answer 18

magnetic field

Question 19

What kind of field does a shortwave with 27.12 MHz produce?

Answer 19

electric field

Question 20

What type of electrodes produce the strongest magnetic fields?

Answer 20

drum type (induction electrode)

Question 21

What type of electrodes produce the strongest electrical field?

Answer 21

air space plates (capacitor electrode)

Question 22

How should the pads be placed to get the strongest electrical field?

Answer 22

close together (center of field is strongest current density)

Question 23

What is the difference between capacitor and induction electrodes?

Answer 23

The patient is not part of the electrical circuit with induction electrodes

Question 24

What are the parameters for shortwave pulsed diathermy?

Answer 24

pulse duration=20-400 microseconds
intensity=up to 1000W per pulse
15-20 minutes
if longer off time than on time is used-allows heat to dissipate and thus not achieving heating effects

Question 25

What are the contraindications of diathermy?

Answer 25

acute and inflammatory injuries
ischemic areas
reduced or absent sensation
fluid filled areas
head and face
malignancies
infection
near reproductive organs
growth plates in bone
metal implants

Question 26

How does microwave diathermy work?

Answer 26

generates strong electrical field

vibrates molecules that are high in polarity

Question 27

What’s the difference between shortwave and microwave?

Answer 27

shortwave units have a greater depth of penetration due to it’s ability to penetrate the fat layer of the body
shortwave is safer

Question 28

What are the indications of diathermy?

Answer 28

post acute injuries
increased blood flow, metabolism, enzyme activity, collagen extensibility, pain threshold, nerve growth and regeneration
enhanced injury recovery
absoption of hematoma
vasodilation
muscle relaxation

Question 29

The shorter the wave the stronger the ______ field. Longer the wave the stronger the ________ field.

Answer 29

Electrical/magnetic